This invention relates generally to a silane-containing material useful as an adhesion promoter in polyurethane systems.
Polyurethane adhesives are commonly used to laminate flexible films for food packaging. The adhesives must not delaminate when the package is filled with liquid ingredients. Silanes are commonly used to maintain adhesion to metal films and impart water and chemical resistance, e.g., N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyl trimethoxysilane (APTMS) and 3-aminopropyltriethoxysilane (APTES) However, phase separation of the silanes may reduce the effectiveness of the relatively expensive silanes. U.S. Pat. No. 5,364,955 discloses adducts of aminosilanes and maleic or fumaric acid. However, there is a need for additional solutions to the problem of silane phase separation.